The present invention relates generally to closures for containers and, more particularly, to safety, i.e., childproof, closures, closures for hermetically sealing containers, tamper-resistant closures, and closures which combine two or more of the safety, hermetic sealing and tamper-resistant functions.
It is desirable and in some cases legally required to provide a closure for containers which will prevent children from obtaining access to dangerous contents, such as medicines, insecticides, cleaners and other toxic household substances, contained therein. Thus, safety or childproof closures have been suggested which are intended to close a container in a manner so as to make it difficult for a child to remove the closure from the container, either intentionally or through inadvertence. Generally, known safety closures must be manipulated in a certain fashion in order to unlock the same from the container to permit its subsequent removal. For example, reference is made to the safety closures disclosed in U.S. Pat. No. 3,182,840 to Polzin, U.S. Pat. No. 3,514,003 to Fitzgerald, U.S. Pat. No. 4,106,651 to Lemons, U.S. Pat. No. 4,187,953 to Turner and U.S. Pat. No. 3,853,237 to Marchant.
However, known safety closures are not entirely satisfactory in use and/or in manufacture. In general, a safety closure should incorporate features which are desirable both from the standpoints of operation as well as manufacture. One desirable feature is that removal of the closure from the container should be possible without requiring maneuvers which are so complicated as to make it difficult for adults, elderly individuals or infirm individuals, to obtain ready access to the contents of the container, yet which are sufficiently difficult to prevent children from removing the closure.
The safety closure should be readily adaptable for use with a wide range of container types and sizes thereby providing an applicability to virtually all packaging styles. However, most safety closures are particularly adapted for use with only certain types of containers. For example, the design of known safety closures typically dictates that the closure be either a threaded or snap-type closure.
In connection with the manufacture of safety closures, it is desirable that the basic design be relatively simple in construction and manufacture. Moreover, it is of course preferable that the closure need not require complicated and therefore expensive molds, or molds which require significant maintenance.
The closure should be reliable and meet all requirements for reliably preserving and storing pharmaceutical and household substances in both liquid and solid form.
Most conventional safety closures also require that the neck of the container to which they are applied be structurally modified to provide the safety locking feature. This is a considerable drawback in that such safety closures cannot be used with containers which are not so structurally modified. Likewise, containers which have been modified for use with a particular type of safety closure cannot be used with closures of different types.
Another desirable feature of a closure, whether of the safety type or otherwise, is that the closure be provided with means for inhibiting unauthorized tampering with the contents of the container prior to the first legitimate removal of the closure therefrom.
In cases where it is desirable or necessary to store the contents of a container under a pressure which is either greater or less than atmospheric, such for example as carbonated beverages, the closure must provide a good hermetic seal. Moreover, when the contents of the container are not exhausted after the initial opening of the container, it is evident that the closure should be capable of reestablishing the over or under pressure as well as the hermetic seal upon being reapplied to the container. Conventional closures having such capabilities are usually of a relatively complicated design and are therefore costly in manufacture. Although closures intended to provide a hermetic seal are known which are of more or less simple construction, such closures often do not provide a reliable hermetic seal, especially after repeated use.
Finally, it may under certain circumstances be advantageous to provide a closure which is capable of functioning simultaneously both as a safety or childproof closure, with or without a tamper-evident capability, while at the same time providing a hermetic seal capability for the contents of the container. To applicant's knowledge, such a closure is not presently available which reliably provides all of the desirable features enumerated above.